1. Field of the Invention
The present invention relates to a manipulator with at least one camera, which has an function of recognizing an object with the camera.
2. Description of the Related Art
In an assembly work using an end effector attached at a tip end of a manipulator, in order to recognize an object to be assembled, and to perform work in various working regions, it is necessary to prepare a camera provided onto the manipulator. Conventionally, as illustrated in FIG. 7A, the camera mounted onto the manipulator mostly has a structure in which a position of a camera 103 is fixed relative to an end effector 101 and the camera 103 is attached at the tip end of the manipulator (see Japanese Patent Application Laid-Open No. 62-277290). However, in the above-mentioned structure, the camera observes the end effector from a fixed direction.
Further, as illustrated in FIG. 7B, as another conventional technology, there is known a structure in which a camera 203, which is rotatable about a Y-axis and a Z-axis, is fixed to a casing of a polyarticular robot so as to always keep an end effector 201 in the field of view, to thereby make the field of view of the camera variable (see Japanese Patent Application Laid-Open No. 63-52990). In the structure, the camera 203 is mounted onto a camera platform 202 rotatable about multiple axes.
However, in the structure illustrated in FIG. 7A (described in Japanese Patent Application Laid-Open No. 62-277290), the camera observes the end effector from the fixed direction, and hence the position of camera 103 is determined by the position of the end effector. That is why the feature of object is sometimes out of the field of view of the camera.
Further, as described in Japanese Patent Application Laid-Open No. 63-52990, in the structure using the camera platform rotatable about the multiple axes, the observing direction of the camera is made variable. However, the camera always merely keeps the end effector in the field of view, and does not cover yaw-axis rotation of the end effector. Therefore, the feature of object is sometimes out of the field of view of the camera. In addition, there may arises an occlusion problem in that one of links of the manipulator or a joint located between the links interposes between the object and the camera and thus the object cannot be seen from the camera.
In view of the above-mentioned problems, it is an object of the present invention to provide a manipulator with at least one camera capable of observing an end effector from a direction suitable for work of the manipulator.